Ohanas and Boma as well. I've been to neither, but both are said to be good for kids - buffet style, so you can get your food fast and he can move around a little.
If you want to try sit down (I don't find buffets relaxing), most Disney restaurants are prepared for kids. But here are some hints. You want to avoid the fanciest places (V&A, California Grill, Flying Fish, Artist's Point, etc. I think all the theme park restaurants are fine, with the possible exception of the expensive one in France) with a "can't sit still" three year old, but their are a ton of "mid scale" sit down restaurants that will be fine for the vast majority of three year olds.
Look at the menu ahead of time so you are ready to order when you are seated. Let your hostess know when you are seated, "he doesn't sit well and we are ready to order, can you send our waitperson right over?" Let the waitperson know the same thing. Your food will usually be at your table really fast.
Skip appetizers, skip dessert - or if you need courses, order them all at once so they can be brought out quickly. Entree and out, if possible. You can stop for dessert at plenty counter service places later (Beavertails, Dole Whips, Mickey Bars, the Pastry shop in France, etc). It isn't the most relaxing, leisurely way to eat a meal, but its better than a week of chicken fingers.
Eat early - 4:30 or 5:00. You'll get seated faster and served faster.
Let your mover walk a little before dinner - don't keep him in the stroller all day. Sounds obvious, but its easy to leave them in the stroller and then wonder why they have so much energy at dinner. You may discover he sits a lot better at Disney than he does at home or if you go out at home - he may be ready for the rest dinner provides. Our kids certainly were.
Make sure they rest, but don't let them over nap. An active kid who wakes up at 4:00 for a 5:00 dinner can be nearly as bad as one that skipped the nap entirely.
We had good luck with our two "non-sitters" We had them at Marrakesh in Morrocco, Whispering Canyon, San Angel Inn in Mexico and the Tempura bar in Japan.